Biosecurity war waged over invasive weeds

Chilean flame creeper is on the list of species Environment Southland wants to get rid of. Photo: File

WEED control in Southland is ramping up as the regional council takes part in a national multimillion-dollar project.

The co-ordinated national research project aimed to tackle six of New Zealand’s most invasive weeds through biocontrol.

It is a three-year, $3.2 million project backed by the Ministry for Primary Industries’ Sustainable Food and Fibre Futures fund, Landcare Research and the National Biocontrol Collective a consortium of regional councils, unitary authorities and the Department of Conservation.

Environment Southland (ES) contributes $26,000 a year to the collective.

ES biosecurity team leader, plants, Jolie Hazley said biocontrol was about future-proofing Southland and the rest of the country against weeds.

ES had been involved in biocontrol programmes for more than 35 years and more than 33 agents had been released.

Ms Hazley noted priority weeds were old man’s beard and Chilean flame creeper.

Old man’s beard is a fast-growing vine able to climb up into the canopy. It smothers and collapses even tall trees and can reduce a forest to an impenetrable, low-growing infestation of the vine.

Chilean flame creeper is invasive along the bush edge and in light gaps where it forms a curtain which smothers native trees and shrubs, and is difficult to remove once established.

Information on pest species was available on the council’s pest hub website.

ES project governance group chairman Phil McKenzie said biocontrol had the potential to provide a longer-term solution at a time when more registered herbicides were being restricted by our export trading countries, weeds were becoming resistant to herbicides, and New Zealand society was demanding more environmentally friendly farming practices.

The three workstreams aimed to advance biocontrol programmes for several high-priority weeds, monitor weed reduction in matured biocontrol programmes on productive land and to develop a partnership for sustaining investment in weed biocontrol.

Its focus was Sydney golden wattle (Acacia longifolia), Chilean needle grass (Nassella neesiana), old man’s beard (Clematis vitalba), woolly nightshade (Solanum mauritianum), Chilean flame creeper (Tropaeolum speciosum), and yellow flag iris (Iris pseudacorus).

By completion, the project aimed to secure Environmental Protection Authority approval for the release of new biocontrol agents for at least three of these six weed species.

Fifteen regional councils were co-investing in the project.